Process of separating zinc or zinc oxid.



1 Erran- STATES. PATEN orrron.

GEORG WANNSCHAFF AND JOSEF SAVELSBERG, 0F PAPENBURG, GERMANY.

PROCESS OF SEPARATING. ZINC 0R ZINC OXID.

No Drawing.

Specification of Letters Patent.

Patented Au. 1,1911.

Application filed March 23, 1911. Serial No. 616,443.

To all whom it may concern:

Be it known that we,GEORG \Vxnxsmmrr Ems. Germany, and JOSEF SAVELSBERG, of ll 5 Bethlehemkanal Rechts, Papenburg-on-the- Ems, Germany, sub]ects of the Klng of Prussia, have invented certain new and useful Improvements'in 'lrocesses for Separating Zinc from Materials \Vhich Contain Metallic Zinc or Zinc Oxid; and we do hereby declare the following to bea full, clear, and exact description of the invention.

This invention relates to a process for the treatment of'-materials which contain 1ne tallic zinc or zinc oxid. such as galvanized metallic waste or other wastes containing zinc, ores or metallurgical products for the purpose of sqiarating the zinc'theretron'i.

It is well known that metallic zinc or zinc oxid can be dissolved in a solution of l zinc chlorid and such a solution of Zinc chlorid has been used already for this purpose. specification of German Patent No. 83812 has already proposed to remove zinc oxid for example from roasted calan'iin and roasted zinc blende by leaching with a zinc chlorid solution and has stated that hydrated oxid of zinc can be separated by cooling or 1 dilution from the solution of zinc oxid so obtained. This statement does not appear to be substantiated by fact. At any rate the experiments which led to the present invcntion showed in every case that by cooling down the zinc chlorid solution containin; the dissolved zinc oxid there was obtained a precipitate consisting of zinc oxychlorid or a mixture of zinc oxid and zinc j chlorid. These experiments also showed that by treating this precipitate with water.

particularly at high temperatures, the greater part of the zinc chlorid can be withdrawn and that by effecting the leaching out 111 a systematic manner so concentrated a solution of zinc chlorid can Without difliculty be finally obtained from this precipitate that the zinc chlorid solution can be used repeatedly and directly for the separation by leaching zinc or zinc oxid from materials containing the same.

According to the present invention it suffices to treat the materials in question with an aqueous zinc ClllOIld solutlon, n a Warm Thus Ho-ptner as described in thel lstate if necessary, whereby. any zinc oxid present is dissolved directly and any metallic zinc present is dissolved with evolu' I tion of hydrogen which gas can be collected l and is, on account of itspurity-capable of l being used to advantage. The solution oh- 1 tained is cooled down and yields a crystalline powder precipitate containing zinc oxid t and zinc chlorid. The residual solution is wzinc chlorid and can be used for leaching Z a further quantity of material to be treated. 1 After decantation or other separation of the zinc chlorid solution t'romthe crystalline powder the latter is treated with preferably hot water, in a systematic manner whereby a further quantity of Zinc chlorid isolution is obtained which can likewise be :used for leaching purposes according to the present invention. In such manner the greater part of the zinc chlorid is recovered repeatedly in the form of a zinc chlorid solution capable of being used. The product which remains atter'this water treatment ialways contains some zinc chlorid alomg with the zinc oxid and comprises an oxychlorid having Zinc oxid in the. proportion jot nine equivalents to one equivalent of zinc chlorid and three molecules of water. This product can be decomposed by alkalis l or the like such for instance as quick lime or sodium hydrate employed for example in l the, form of milk of lime. or soda lye into pure zinc oxid. the chlorin in this compound igomg into solution as a chlorid. such as sodium chlorid, calcium chlorid. 1 The process possesses the great advantage of cheapness inasmuch as but little of the l l l l zinc chlorid needs to be replaced and usually I the work can be carried on with the same zinc chlorid solution and the zinc obtained in the form of a good zinc oxid capable of use.

When treating galvanized iron waste for example the process is carried out as'follows The waste is treated in suitable vessels. iron for example, with aqueous solu- 1 tion of zinc chlorid heated to boiling, until l it no longer takes up zinc or until no more hydrogen is evolved. The zinc chlorid solution containing the zinc oxid is then run off and allowed to cool. As it c ols zinc oxychlorid se arates out in a crytalline form. The c ear supernatant solution is used to dissolve fr sh quantities of zinc. Residual zinc chlorid is dissolved out of the crystalline residue with water whereby an oxychlorid of the formula remains. More complete extraction of zinc chlorid can be obtained by prolonged boiling with water. It has even been found possible to so completely dissolve out the zinc chlorid that the ratio between it and the oXid is as l to 19. The extracted zinc chlorid is converted into zinc oXid and calcium chlorid by treatment with lime so that after washing out the calcium chlorid ure zinc oxid remains behind. The ch orin separated out as calcium chlorid in this reaction, the quantity of which 1s comparatively small, is replaced by additions for instance of fresh zinc chlorid solution or hydrochloric or sulfuric acid.

We claim:

1. The method of separating zinc or zinc oxid from material containing the same,

which comprises leaching the material with a heated aqueous solution of zinc chlorid, cooling the solution to obtain-a precipitate containing zinc oxid and zinc chlorid leaching the precipitate with. Water to remove the greater part of the zinc chlorid, and 2 treating the residue with an alkali to con-- I vert all ofthe zinc salts therein into zinc oxid.

2. The method of separating zinc or zinc oxid from material containing the same, which comprises leaching the material with a heated aqueous solution of zinc chlorid, cooling the solution to obtain a precipitate containing zinc oxid and zinc chlorid, leaching the precipitate with water to remove the greaterpart of the zinc chlorid; and treating the residue with lime to convert all of the zinc salts therein into zinc oxid.

3. The method of separating zinc or zinc oXid from material containing the same which comprises leaching the material with a boiling aqueous solution of zinc chlorid,

cooling the solution to form a precipitate,

separating precipitate and solution, leaching the precipitate with water, utilizing both of the resulting solutions for the treatment of new quantities of-material and treating the solid residue with lime to obtain the zinc in the form of oxid.

In testimony that we claim the foregoing as our inventionwe have signed our names in presence of two subscribing witnesses.

GEORG WANNSCHAFF. JOSEF SAVELSBE-RG, Witnesses:

FERDINAND REICHY, FREDERICK HOYERMANN. 

